I don't know how long this has been going on, but I found out just today - the hard way - that TextNow's free wifi plan is now totally useless for incoming verification texts (like the ones sent by Amazon to verify your account etc.)
TextNow just refused to show me the verification code, telling me I needed to pay up for the privilege. Huge bummer to me!
This was on their wifi-only plan. I haven't checked my Free Cellular plan yet. Sure hope they haven't done the same thing there. They'll lose me for sure if they gouge me on verification texts.
The charge is $5/year-- and it's not specifically for verification texts, but to guarantee that TextNow will not expire your number for non-use.
TextNow does have to buy blocks of numbers to give away for free, and this was apparently becoming a burden as their free customer base grew.
They've always expired numbers if they're not used often enough (which seems to vary...), and at least for a while they were expiring numbers quicker, and re-issuing them to someone else quicker, because of that first issue....
Honestly, using a TextNow number for verification is a security risk to you, if there's a reasonable chance that your number will get expired and end up in someone else's hand. The $5 annual charge seems reasonable to me to eliminate that risk. I also understand why TextNow might not want to get stuck getting blamed for that situation.
The other view... TextNow found the $5 charge more profitable than they imagined, and decided to encourage folks to do that. Take your pick.
Like almost all businesses who give away something for free, they may not be that concerned if they lose your business, as long as it doesn't eliminate too high a percentage of their customer base.